The racecourse's wifi network is called ParisLongchamp.
To access it:
1 / Enable wifi on your smartphone.
2 / Choose the "_ParisLongchamp" network.
3 / On the screen that appears, enter your name and mobile number.
5 / Check the box I want to receive communications from France Galop.
6 / Click the Connect button.
7 / You will receive an SMS with a link.
8 / This link opens your browser and gives you access to the screen of the services offered on the racecourse.